The rule for every saw applies here: at least three teeth must be engaged, or the work catches between teeth and strips them. Thin wall tube therefore needs a fine blade, 24 or 32 TPI.
For solid bar, a coarser 18 TPI blade clears chips better and cuts faster. Bi-metal blades cost slightly more and outlast carbon-steel ones by a wide margin.
The questions welders ask
Why do my blades break at the pin?
Usually over-tension combined with twisting in the cut, or a frame that flexes. Tension the blade firmly but keep the stroke straight, and let the weight of the saw do the cutting on the forward stroke — a hacksaw only cuts one way, and forcing it on the return is what snaps blades.
Last reviewed 2026-08-14